March 6, 2010

Both China clay and Ball clay belong to the kaolin group. Although the primary constituent is Kaolinite in both of them, the latter has greater plasticity and lesser refractoriness owing to the presence of Montmorillonite in considerable amounts. So, ball clay is normally added to china clay to achieve greater strength, increase refractoriness and the required plasticity. To discuss all aspects of ‘China Clay’ in one post would be quite a long one and a reader who is searching a specific topic about china clay, may not like to go through the whole article. So, we have divided the different topics of china clay like - its beneficiation, improvement in its quality (benefit) after different treatments of beneficiation, characteristics (properties) of china clay required for different industries etc. into separate posts. Here we will discuss the following:

=> Properties and occurrences of china clays particularly in India.

=> Uses of china clay in general.

=> A few addresses of Mines (also Suppliers) of Indian china clays along with their sample Test Reports given at the end.

Properties and Occurrences of China Clay in India

As for genesis, both China clay and ball clayare the products of weathering processes of feldspathic rocks. What happens during weathering that the silica and iron oxides are partially leached with the residue (essentially an aluminium silicate in composition) forming the in-situ deposits. Depending upon the efficiency of the weathering process, the impurities like grit i.e. siliceous particles and iron oxide minerals exist in different percentages in different clay deposits.

India has extensive deposits of china clays distributed in almost all states. However, good deposits are found Chaibasa, Singhbhum (near Ranchi, Jharkhand), Mokdum Nagar, Kharidumri, Suri, Qasim Bazaar all in Bankura, Birbhum districts (West Bengal), Barmer, Pali, Bikaner, Ajmer, Nim-ka-Thana, Udaipur (Rajasthan), Anantpur, Nellore and Guntur (AP), Chanda, Ratnagiri (Maharashtra), Udhampur (J & K). Very good quality china clays are found in Kerala in Kundra (Quilon), Ernakulam and Trivandrum districts. The estimated total reserve of crude clay is around 7.5 lakh tones. The spray dried kaolin is marketed under the trade name “Kundara Kaolex”. The average chemical analyses of some Indian china clays are presented in the following table.

Table: Chemical Compositions (in %) of some Indian China Clays

SOURCE

SiO2

Al2O3

Fe2O3

TiO2

CaO

MgO

K2O

Na2O

LOI

Gujarat

Kutch Minerals

Ashapura

AMI China Clay

Eklera

47.75

49.63

52.45

48.92

34.25

34.00

29.83

33.60

0.90

0.60

0.94

1.30

1.30

1.37

1.48

1.12

1.23

0.54

1.14

0.65

0.24

0.58

0.59

0.28

0.35

0.22

0.35

1.00

0.45

0.61

0.86

0.31

12.45

12.20

11.90

12.80

Bihar - Jharkh

Rajmahal (pink)

Rajmahal (white)

Chaibasa - I

Chaibasa (S.Fine)

Simultala

46.68

48.90

47.90

46.59

47.30

35.29

34.51

36.00

35.95

38.20

1.90

1.71

1.25

1.12

0.47

0.90

0.50

Tr.

Tr.

0.07

0.28

0.67

1.24

1.40

0.35

0.50

0.20

0.40

0.40

0.10

0.28

0.41

0.61

0.33

1.55

0.60

0.52

0.75

0.90

0.15

13.12

12.60

12.25

13.22

11.80

West Bengal

Mokdum Nagar

Mohammad Bazaar

44.10

44.30

37.39

36.69

2.60

2.10

1.37

0.80

0.10

0.30

Tr.

0.26

0.20

0.60

0.75

0.29

13.48

14.35

Rajasthan

Modi Clay (P-90)

Modi Clay (TT-75)

44.46

46.82

37.03

36.70

0.80

1.00

Tr.

0.20

2.00

0.70

0.41

0.25

0.07

0.15

1.02

0.20

14.65

13.87

Kerala

Marthandamkonam

Kundara, Quilon

English India

Chilambil, Trvndrm

Sasthavattom

46.47

45.83

46.30

45.60

44.11

38.13

38.17

38.80

37.40

38.17

0.28

1.43

0.50

0.75

1.30

0.79

0.40

0.10

0.90

1.55

Tr.

0.90

0.02

Tr.

Tr.

0.59

0.12

0.07

0.41

0.04

0.02

0.25

0.07

0.02

0.02

0.08

0.72

0.08

0.02

0.43

14.20

14.00

14.10

14.85

14.26

Tamil Nadu

Neyveli Clay

45.00

36.72

0.38

1.75

0.55

Tr.

0.03

0.24

14.24

Uses of China Clay

China clay is used in rubber, ceramic, textile, paint, pharmaceutical, paper, cosmetic industries and also as in refractory industry for the production of insulation bricks, insulation mortars and castables [Refer to our separate post Use of China Clay as Raw Material in the Production of Refractory Insulation Bricks].

In ceramics china clay is widely used in manufacturing earthenware, fine china, stoneware, tiles, pipes etc. Usage of china clay for ceramic industry depends on factors like - plasticity, shrinkage after drying and on firing, colour on firing, refractoriness etc. The grit content should be around 1%.

As a decolouriser of oils it is known as ‘Fuller’s Earth’. Mixtures of china clays and montmorillonites are also used as cracking catalysts for heavy petroleum fractions. Other areas of limited use are leather, paint, plastics, soaps, polishing compounds, emulsifying agents etc.

Mines and Suppliers

Below are addresses of some of the above mentioned mines (also suppliers) of china clays of different grades form Bihar, Jharkhand and West Bengal whom I visited during 2005 - 2006 accompanied by the test results of the china clay samples that were drawn and collected by myself during my visits to these mines.

Chaibasa (Singhbhum) China Clay

Address:

Singhbhum Mineral Co., Post Box No. - 24, Station Road, PO- Chaibasa

PIN - 833 201 (Jharkhand).

Contact person:HemantRathore (Mine owner)

Tel: 91-6582-256551/258336

Mob: 91-9431110051.

Mine address:

Singhbhum Minerals, Hatgamharia, Chaibasa (Jharkhand).

Sample Test Report (average report):

1. Sample = China clay (RT grade), drawn from Pit No.9.

Total Shrinkage (after drying & firing 1330OC/2 hrs) = 15%

Characteristics = White, clean, no spot.

LOI % - 11.6

Al2O3% (min) - 36.0

Fe2O3% (max) - 1.7

TiO2% (max) - 0.15

2. Sample = China clay (pink variety)

Total Shrinkage (after drying & firing 1330OC/2 hrs) = 17%

Characteristics = Pinkish White, clean, no spot.

LOI % - 11.5

Al2O3% (min) - 33.52

Fe2O3% (max) - 3.04

TiO2% (max) - 0.15

3. Sample = China clay (RT grade, upper layer) drawn from Pit No.9.

Total Shrinkage (after drying & firing 1330OC/2 hrs) = 15%

Characteristics = White, clean, no spot.

LOI % - 11.6

Al2O3% (min) - 36.28

Fe2O3% (max) - 1.9

TiO2% (max) - 0.12

Mine address:

D.M.Minerals,Gondkida Mines, Hat Gamharia, Chaibasa (Jharkhand).

Sample Test Report (average report):

1. Sample = China clay (Special/Rubber grade)

Total Shrinkage (after drying & firing 1330OC/2 hrs) = 16%

Characteristics = Milky white, clean, without any spot.

LOI % - 14

Al2O3% (min) - 36.0

Fe2O3% (max) - 1.92

TiO2% (max) - 0.25

2. Sample = China clay (crude, unwashed)

Total Shrinkage (after drying & firing 1330OC/2 hrs) = 12%

Characteristics = Pinkish White, clean, no spot.

LOI % - 13.8

Al2O3% (min) - 36.00

Fe2O3% (max) - 1.96

TiO2% (max) - 0.02

3. Sample = China clay (SF grade)

Total Shrinkage (after drying & firing 1330OC/2 hrs) = 16%

Characteristics = Milky white, clean, no spot.

LOI % - 14.4

Al2O3% (min) - 36.44

Fe2O3% (max) - 1.39

TiO2% (max) - 0.40

Address:

Gupta Minerals, PO- Hat Gamharia, Dist.- West Singhbhum

PIN - 833 214 (Jharkhand).

Contact person:Ajay Kr. Gupta (Mine Owner & Supplier)

Tel: 91-6589-285267

Mob: 91-983213463, 91-9835142033

Sample Test Report (average report):

Sample = China clay (SF grade)

Total Shrinkage (after drying & firing 1330OC/2 hrs) = 17%

Characteristics = Buff, Off-white.

LOI % - 10.0

Al2O3% (min) - 33.0

Fe2O3% (max) - 2.8 - 3.0

TiO2% (max) - 1.0

(CaO + MgO) - 0.5

Na2O - 0.88

K2O - 1.38

PCE - 30 (Orton)

Address:

ChotanagpurCommercial Corpn. (P) Ltd.

Post Box - 54, Chaibasa Dist.- West Singhbhum

PIN - 833 201 (Jharkhand).

Contact person:R.P. Rungta (Supplier)

Tel: 91-6582-256062, 91-33-22101235/1236

Mob: 91-9431110291

Sample Test Report (average report):

Sample = China clay

Total Shrinkage (after drying & firing 1330OC/2 hrs) = 14 - 15%

Characteristics = Yellowish white, clean.

LOI % - 12.0

Al2O3% (min) - 31.38

Fe2O3% (max) - 3.36

TiO2% (max) - 0.30

PCE - 29 - 30 (Orton)

Lohardaga China Clay (Near Ranchi, Jharkhand)

Address:

Regal Sales and Marketing, Lohardaga, Ranchi

Sample Test Report (average report):

Sample = China clay (INDAL Type)

Total Shrinkage (after drying & firing 1300OC/2 hrs) = 7%

Characteristics = Milky white, clean.

LOI % - 14.0

Al2O3% (min) - 37.00

Fe2O3% (max) - 1.35

TiO2% (max) - 3.0

PCE - 32+ (Orton)

Bhilwara (Rajasthan) China Clay

Address:

Bhilwara China Clay Suppliers

Main Bazaar, Bhilwara (Rajasthan)

Sample Test Report (average report):

Sample = China clay

Total Shrinkage (after drying & firing 1400OC/2 hrs) = 16%

Characteristics = Greenish white, clean, minor crizzling.

AP = 5.5

BD = 2.5 gm/cc

LOI % - 13.5

Al2O3% (min) - 37.0

Fe2O3% (max) - 1.4

TiO2% (max) - 4.0

PCE - 32 (Orton)

Suri, Birbhum China Clay (West Bengal)

Address:

A.K.Industries Pvt. Ltd.,

P-7, Dr. Suresh Banerjee Road, Kolkata - 85.

Tel: 91-33-23505765/25348349/25533737

Mob: 91-9831219022

Contact person:Soumendu Nag

Mob: 91-9434007964.

Mine address:

A.K. Industries Pvt. Ltd. Village - Kalipur

P.O.-Barabagan, Suri

Dist. - Birbhum (WB).

Tel: 91-3462-225423

Sample Test Report (average report):

1. Sample = China clay

Total Shrinkage (after drying & firing 1400OC/2 hrs) = 18%

Characteristics = White, clean.

AP = 10%

BD = 2.42

LOI % - 14

Al2O3% (min) - 37.0

Fe2O3% (max) - 2.3

TiO2% (max) - 2.5

PCE = 33 (Orton)

Address:

Patelnagar Minerals & Industries Pvt. Ltd. (PMI),

20B, Abdul Hamid Street (1st Floor), Kolkata - 700069.

Tel: 91-33-22486915/22486928/23371276

Fax: 91-33-22489546

Contact person:A.Ahmed (Chief Executive)

Tel: 91-3462-260245/260213

Mines and Refinery address:

PMI Private Ltd., Patelnagar, Suri

Dist. - Birbhum (WB)

Tel: 91-3462-260225/260223

Sample Test Report (average report):

Sample = China clay (Refractory grade)

[All grades of china clay are available with them suitable for rubber, textile, cosmetic, paint and paper industries.]

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